The clubhead of an iron needs to be moving down slightly at impact, so it bottoms out just on the target side of the ball and produces a shallow divot that starts in front of the ball.

Different faults produce different divots. Players who swing too much from the inside bottom out behind the ball. Players with outside-in swings have overly steep paths and produce deep divots.

The next time you’re at the driving range, try the following experiment: Draw a line in the grass and make some swings, trying to start the back of the divot at the line. It may seem easy to do, but it really isn’t.